.calendar{
  border: 1px solid #000;
  width: 300px;
  height: 250px;
  padding: 10px;
}
.header{
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 40px;
}
.days{
    display: flex;
    flex-wrap: wrap;
}
.empty,  .day{
    width:calc(100%/7);
    text-align: center;
    line-height: 30px;
}
.day:hover,.selected{
    background-color: #ccc;
    cursor: pointer;
}
